Water hammer is a common problem in domestic water plumbing systems. The negative effects of water hammer include damage to pipes and pipe fittings due to vibration, shock, and physical displacement, as well as annoyance due to the loud noises generated. Existing solutions have relied on pressure regulators to control pressure surges or surge tanks. Both have disadvantages. Pressure regulators require adjustment at installation and periodically after installation. Small clearances within pressure regulators can get plugged by particles or mineral buildup common in domestic water systems rendering them inoperable, or requiring strainers or screens. Pressure regulators designed for domestic water systems also don't operate fast enough to stop a water hammer event. Surge tanks combined with check valves can aid in reducing water hammer, but surge tanks impose significant space requirements and generally cannot be located near enough to each of the sources of water hammer events to prevent the pressure waves from traveling throughout the piping system.
Thus, there is a need for a compact water hammer prevention device that is compact, simple, inexpensive, virtually maintenance free, and self-flushing, which can be installed in domestic piping systems close to the source of water hammer events.
Automatic drain trap primers are known in the art. Automatic drain trap primers port small amounts of water to drain in order to maintain water seals in drain traps that prevent sewer gases from leaking back through drain pipes. Automatic drain trap primers generally work based on pressure fluctuations in domestic water supply systems. When water pressure in the domestic water supply line drops due to a valve opening, such as a faucet or a toilet flushing, the drain trap primer valve cycles and ports water to drain. Drain trap primers, however, provide no protection from water hammer. Automatic drain trap primers, moreover, tend to be vulnerable to leakage because they must be adjusted to the anticipated system pressure—if the nominal system pressure persists below the pre-set pressure, then the pre-set automatic drain trap primers may continuously port water to drain. Some drain trap primers have attempted to solve this problem of leak by, but they still lack the ability to protect against water hammer events.
Thus, there is also a need for an automatic drain trap primer that automatically adjusts to varying domestic water supply line pressures, that is compact, simple, inexpensive, virtually maintenance free, and which provides protection from water hammer.
Presently known art attempts to address this problem, but has not completely solved the problem. The following represents a list of known related art:
Reference:Issued to:Date of Issue:U.S. Pat. No. 6,152,164WhitesideNov. 28, 2000U.S. Pat. No. 5,678,588Perrott, et alOct. 21, 1997U.S. Pat. No. 5,287,877AckroydFeb. 22, 1994U.S. Pat. No. 5,263,508PerrottNov. 23, 1993U.S. Pat. No. 4,497,337Mosbrucker, et alFeb. 5, 1985U.S. Pat. No. 4,204,556SullivanMay 27, 1980U.S. Pat. No. 3,422,835WattsDec. 20, 1965U.S. Pat. No. 3,333,597SullivanNov. 5, 1964U.S. Pat. No. 2,096,287McDougallApr. 17, 1937
The teachings of each of the above-listed citations (which does not itself incorporate essential material by reference) are herein incorporated by reference. None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed.